1. Field of the Invention
The present invention relates to a magnetooptical information recording/reproducing apparatus and method, which can erase and rewrite information on a disk-shaped magnetooptical recording medium and, more particularly, to a magnetooptical information recording/reproducing apparatus and method corresponding to a magnetic field modulation type overwrite-capable magnetooptical recording medium.
2. Related Background Art
Conventionally, the performance of a magnetooptical recording method based on a magnetic field modulation method has been sufficiently improved so as to achieve short recording, reproduction, and erase times, a large capacity, and high-speed access. Such a magnetooptical information recording/reproducing apparatus has a construction, as shown in, e.g., FIG. 1. More specifically, seek operations of both an optical head (optical pickup device) 103 and a magnetic head 108 are simultaneously performed by a seek motor. The seek motor is constituted by a linear motor coil 104 provided on the optical head 103, and a magnetic circuit arranged along a guide 107 for guiding the optical head 103 and including a magnet 106 and a yoke 105. The magnetic head 108, which opposes the optical head 103 to sandwich a recording medium therebetween, is mounted on a floating slider. The slider is mounted on a coupling member 110 via a support beam (suspension) 109, and the coupling member 110 is fixed to the optical head 103.
The optical head 103 comprises an actuator 102 for two-dimensionally driving its objective lens 102a, and can finely adjust the tracking and focusing directions of the objective lens 102a. A seek operation in the radial direction of a magnetooptical recording medium 101 is attained by current control for the linear motor coil 104, as described above, and tracking and focusing operations in recording and reproduction modes are attained by current control for a corresponding coil of the actuator 102. In this case, the tracking control of the objective lens 102a by the actuator 102 is limited to a movable range of the objective lens 102a. When a tracking error is large, and exceeds the movable range, tracking control of the optical head 103 itself is performed using the above-mentioned seek motor.
However, in the above-mentioned construction, the relative position between the optical head 103 and the magnetic head 108 must be adjusted with high precision since it influences data reproducibility of magnetooptical recording media compatible to a magnetooptical disk apparatus. Thus, the apparatus must be assembled with strict care. However, since the magnetic head 108 is mechanically coupled to the optical head side via the support beam (suspension) 109, it is difficult to adjust the apparatus with required precision, and such adjustment requires considerable time. When the apparatus is used, a change in volume of the mechanical coupling portion occurs due to a change in temperature in the apparatus, and this may shift the relative position between the optical head 103 and the magnetic head 108. In this manner, when the relative position adjustment precision is lowered, recording may be performed to disturb data reproducibility even within the fine adjustment movable range of the objective lens 102a by the actuator 102.